Alignment and positioning equipment are important as they are required in nearly all research and manufacturing processes. Conventionally, translation stages are used extensively in the industry for alignment and positioning. Translation stages provide a motion or a translation when a force is applied onto them. The motion may be a desired end action, or the motion may be a way to measure the force applied onto or by the translation stage. In the former case the translation stage is used to position or move objects, while in the latter case the stage is used to measure or sense a force. Translation may be linear, or rotational, or a combination of both. Translation maybe along one axis or along several axes.
Some existing translation stages employ transducers to provide a signal that is a function of the translation stage position with respect to a reference frame. Often these translation stages measure or monitor electrical or magnetic parameters to determine their position. These translation stages may be affected by electromagnetic fields and the results may not be very accurate. Conversely, electrically powered translation stages may also create perturbation in the surrounding EM field. This is particularly undesirable in instruments based on magnetic resonance. Moreover, since most translation stages are opaque, their use is constrained in many applications, for example to move samples under a microscope, or to perform spectroscopy.
Further, some transducers measure or monitor optical parameters to determine the translation stage position. These are known as optical transducers. Optical transducers are known in the art and generally employ a light-source and an optical-detector and some means to vary an intensity of light falling on the optical-detector in accordance with the displacement of the translation stage. However, the accuracy of these translation stages that use optical transducers can be affected by vibrations, high temperatures, temperature changes or air turbulence.
Translation stages are generally made of metal. More recently, some microstages have been made of silicon. Most of the existing translation stages, which incorporate position transducers, are non-monolithic devices. They are made of multiple pieces, often of different materials, which are fastened together. High accuracy translation stages are factory calibrated. The calibration and general performance of the devices are susceptible to vibrations and the manufacturing is rather complex. Furthermore, in some cases, calibration procedures have to be performed regularly to maintain a desired level of accuracy. Therefore, most of the existing translation stages are affected by high temperature, electromagnetic fields, vibrations, shocks and air turbulences. Most existing translation stages are also subject to wear. Furthermore they may not be compatible with chemically sensitive applications.
Therefore, there is a need for a translation stage which gives accurate results and which is not, or less, affected by high temperatures, electromagnetic fields, vibrations, shocks, air turbulences, and chemically corrosive or sensitive environments.